Flow in the Plattengneis shear zone (eastern Alps, Austria)

Autor(en)

Luke Thomas Hill, Michel Bestmann, Bernhard Grasemann

Abstrakt

The Plattengneis Shear Zone (PGSZ) serves as a major high-P-T crustal-scale shear zone in the Koralpe (SE Austria). Despite this, no descriptions of convincing monoclinic kinematic indicators have been published. Only orthorhombic fabrics parallel to the prominent N-S stretching lineation have been described, leaving the full kinematic history unresolved. Here, unequivocal monoclinic fabrics, perpendicular (E-W) to the stretching lineation are presented with a previously undescribed top-W shear sense. This macroscopic data is integrated with new micro- and crystal-scale PGSZ quartz data (crystallographic preferred orientations, CPO; misorientation axes; crystalline vorticity axes, CVA) to inform a newly proposed model for the Eo-Alpine kinematics of the Koralpe. A dominant signal of pure shear succeeded by a partial-overprint of simple shear is presented from the preserved record of crystal-plastic deformation. The two deformations are approximated to the macroscopic D₁ orthorhombic pure shear (N-S) and D₂ monoclinic simple shear (E-W) fabrics. Misorientation axes and CPO reveal a dominant activity of the prism< a > slip system which has positive geometric compatibility with the D₁ stress field. However, the stress orientations for D₂ simple shear are incompatible for continued prism< a > slip. Other major slip-systems (rhomb< a >, prism-[c]) remain unfavourably orientated for further strain accommodation. Instead, a partial D₂ overprint is proposed, relying upon several different slip-systems for the accommodation of D₂ kinematics. This multi-scale kinematic model for the PGSZ has wider tectonic implications, establishing a possible connection to the Eo-Alpine displacement and exhumation history.

Organisation(en)

Institut für Geologie

Journal

Journal of Structural Geology

Band

210

ISSN

0191-8141

DOI

https://doi.org/10.1016/j.jsg.2026.105741

Publikationsdatum

09-2026

Peer-reviewed

Ja

ÖFOS 2012

105124 Tektonik

Schlagwörter

ASJC Scopus Sachgebiete

Geology

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/101c7ed8-0b08-4dd6-8a2f-4ff643620f42